Safety apparatus for mechanical filing cabinets

ABSTRACT

This disclosure describes a safety apparatus for use in a mechanized filing cabinet. A lower bar having a lamp at one end and a photocell at the other end is attached by springs to the rear of the posting board of the filing cabinet. An upper bar also having a lamp at one end and a photocell at the other end is attached by springs to the bottom of the closure door of the filing cabinet. When either of the photocell beams is broken, the motor that moves the trays of the filing cabinet is deenergized. In addition, when the door is closed, the upper bar impinges on rubber stops causing the upper bar to move upwardly. The upward movement of the upper bar opens microswitches which are also connected to deenergize the tray movement motor.

United States Patent Kanitz 1 Feb. 8, 1972 [541 SAFETY APPARATUS FOR MECHANICAL FILING CABINETS [72] lnventor: Roy Edwin Kanitz, Belpre, Ohio [73] Assignee: Sperry Rand Corporation, New York,

[22] Filed: Dec. 10, 1969 21 Appl. No.: 883,690

[52] U.S.Cl ..3l2/223 [51] Int. Cl 7b 77/08, A47b 81/00 [58] Field of Search ..312/223 [56] References Cited UNITED STATES PATENTS 3,059,984 10/1962 Handel 3,224,824 12/1965 Sturgis et a1. 3,480,343 11/1969 Kanitz ..312/223 Primary Examiner-Paul R. Gilliam Attorney-Marshall M. Truex, Frank A. Seemar and Griffin, Branigan and Kindness [57] ABSTRACT This disclosure describes a safety apparatus for use in a mechanized filing cabinet. A lower bar having a lamp at one end and a photocell at the other end is attached by springs to the rear of the posting board of the filing cabinet. An upper bar also having a lamp at one end and a photocell at the other end is attached by springs to the bottom of the closure door of the filing cabinet. When either of the photocell beams is broken, the motor that moves the trays of the filing cabinet is deenergized. In addition, when the door is closed, the upper bar impinges on rubber stops causing the upper bar to move upwardly. The upward movement of the upper bar opens microswitches which are also connected to deenergize the tray movement motor.

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FIG. 5

ATTORNEYS SAFETY APPARATUS FOR MECHANICAL FILING CABINETS BACKGROUND OF THE INVENTION This invention relates to filing cabinets and more particularly to mechanized filing cabinets wherein a plurality of trays are moved through an orbit of travel by a motor. This movement allows access to the trays via an access opening in the front of the cabinet. Preferably, the orbit of travel is in a vertical plane and the trays may be moved in either direction, depending upon the location of a particular tray when it is desired to move it to the access opening. Filing cabinets of this nature generally have a posting board that projects outwardly from the access opening. The posting board is movable upwardly and downwardly so that the operator of the filing cabinet can either sit or stand, as desired. In addition, a moveable posting board allows operators of varying heights to use the filing cabinet.

One prime disadvantage of prior art mechanized filing cabinets is that the trays must be moved slowly through their orbit of travel in order that they can be quickly stopped. That is, a file of a tray located behind the access opening may project through the opening when the trays are moved by energization of the motor. Alternatively, an operator may reach into one of the filing trays when the trays are moving. In either event, tray movement must be immediately stopped, hence, the trays must be moved slowly.

One prior art attempt to solve the foregoing problem is described in US. Pat. No. 3,224,825 issued to Charles P. Sturgis et al. for Power File Counter Construction. That patent describes locating a plurality of photocells along one side of the access opening and a plurality of aligned lamps along the other side of the opening. The photocells are connected to the circuit applying power to the motor driving the trays. When the beam of one or more of the lamps is broken, the motor cannot be energized. The primary disadvantage of the system described in the foregoing patent is that it requires the use of more than a minimum number of photocell-lamp combinations. In addition, the location of the posting board is fixed by the location of the lamp-photocell arrangements. Consequently, the posting board is not easily adjustable for operators of varying heights.

Another disadvantage of some prior art mechanized filing cabinets is that the filing trays can be moved even though the door closing the access opening is locked. That is, even though the door closing the access opening is locked, the controls for causing tray movement are not locked. Hence, the files can be moved through their orbit of travel by unauthorized persons.

Therefore, it is an object of this invention to provide a safety apparatus for use in a mechanized filing cabinet.

It is another object of this invention to provide a safety apparatus for use in mechanized filing cabinets that includes a minimum number of photocell-lamp combinations.

It is also an object of this invention to provide a safety apparatus for use in mechanized filing cabinets that prevents the operation of the controls causing movement of the filing cabinets trays when the access opening door of the cabinet is closed.

It is yet another object of this invention to provide a safety apparatus for use in a mechanized filing cabinet that allows the posting board to be located in essentially an infinite number of positions, while providing maximum protection to the operator of the filing cabinet.

SUMMARY OF THE INVENTION In accordance with a principle of this invention, a safety apparatus for use with a mechanized filing cabinet is provided. The safety apparatus comprises an upper bar and a lower bar. Each bar has a light-detecting element mounted on one end and a lamp mounted on the other end. The upper bar is springably attached to the lower edge of the door of the filing cabinet and the lower bar is springably attached to the rear edge of the posting board. The light-detecting elements are connected to the tray movement motor in such a manner. that the motor cannot be energized when the light beam impinging on either light-detecting elements is broken.

In accordance with a further object of the invention, the upper and lower bars include elements that impinge on the arms of microswitches. The microswitches are closed when the door is open. However, when the door is closed, the upper bar impinges on rubber stops and is moved upwardly. This movement opens the microswitches. The microswitches are also connected to the tray movement motor in such a manner that the motor cannot be energized when the microswitches are open.

It will be appreciated from the foregoing summary of the invention that a safety apparatus for use with a mechanized filing cabinet is provided. Only two sets of light-detecting ele- V BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects and many of the attendant advantages of this invention will become more readily ap preciated from the following detailed description of a preferred embodiment of the invention when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a front view of a mechanized filing cabinet;

FIG. 2 is a diagram of the backside of the access opening door of the filing cabinet illustrated in FIG. 1 and includes a portion of the apparatus of the invention;

FIG. 3 is a cross-sectional view along line 3-3 of FIG. 2;

FIG. 4 is pictorial diagram illustrating a portion of the invention attached to the posting board;

FIG. 5 is an end view of the pictorial diagram illustrated in FIG. 4; and,

FIG. 6 is an electrical schematic diagram.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates a mechanized filing cabinet I] having an access opening 13 behind which a plurality of file trays 15 pass. The trays are moved through a vertical orbit of travel by a motor (not shown). An operator l7 sitting in front of the access opening on a conventional secretarial chair I), is also illustrated in FIG. 1. Located in front of the operator at approximately waist level is a posting board 21. Located on the upper surface of the posting board but not shown are a plurality of pushbutton switches which control the movement of the trays 15 past the access opening 13. That is, when a particular pushbutton is pressed, the motor is energized and moves a particular tray 15 to the access opening 13. Located at the top of the access opening 13 is a sliding door 23. When the handle 25 is pulled downwardly, the door 23 slides down until it meets the posting board 21, and closes the access opening 13.

Turning now to the invention, an upper bar 27 is attached to the lower edge of the door 23 and has a photocell housing 29 shown in dotted form in FIG. 1 at one end. A lamp housing 31 is located at the other end of the bar 27 and is also shown in dotted form in FIG. 1. The invention also includes a lower bar 33 mounted at the rear edge of the posting board 21. A photocell housing 35 is located at one end of the lower bar 33 and a lamp housing 37 is located at the other end of the lower bar 33. From the foregoing description and viewing FIG. I, it is to be understood that the lamps in lamp housings 31 and 37 project light beams that impinge on the light-sensitive surface of photocells held in the photocell housings 29 and 35. respectively.

FIG. 2 is a rear view of the sliding door 23. Mounted on either side of the door 23 in parallel are first and second U- shaped brackets 41 and 43. The U-shaped brackets 41 and 43 are preferably formed of flat pieces of metal and have outwardly projecting horizontal flanges. First and second rods 45 and 47 slidably pass through apertures in the outwardly projecting flanges on the first and second U-shaped brackets 41 and 43, respectively. Bushings 49, 51, 53 and 55 preferably formed on nylon or a similar material, surround the rod in the apertures in the flanges. The shafts 45 and 47 are about twice the length of the brackets between the flanges and project downwardly below the brackets to about the lower edge of the sliding door 23.

Third and fourth similarly fonned U-shaped brackets 57 and 59 also have flanges that fit about the first and second rods 45 and 47, respectively. The third and fourth U-shaped brackets are mounted at right angles to the first and second U- shaped brackets 41 and 43 with their connecting portions pointed inwardly. The third and fourth U-shaped brackets are slidably attached to the first and second rods 45 and 47. The inward or connecting portions of the third and fourth U shaped brackets are separately connected to vertical outwardly extending flanges of first and second plates 61 and 63 in any suitable manner, such as by spot welding, for example. The firstand second plates 61 and 63 also have upper projections that project past the lower flanges of the first and second U-shaped brackets 41 and 43. The upper projections have horizontal outwardly projecting tabs 65 and 67. The tabs 65 and 67 impinge on the arms of first and second microswitches 69 and 71 which are attached via suitable mounting brackets 73 and 75, to the rear face of the sliding door 23. More specifi cally, the counting brackets 73 and 75 are attached by adjustment bolts 77, 79, 81 and 83 to plates 78 and on which are mounted the first and second microswitches 69-and 71.

The lower portions of the first and second plates 61 and 63 are attached to the ends of the upper safety bar 27 by welding, for example. In addition, the lower flanges of the third and fourth U-shaped brackets 57 and 59 are attached to the first and second plates by any suitable means, such as welding, for example. Located in between the lower flange of the first and second U-shaped members and the upper flange of the third and fourth U-shaped members and projecting outwardly are L-shaped (inverted) support members 87 and 89. The support members are slidably attached along their vertical legs to the inner side of the edges of the sliding door 23 by means of plastic guide blocks 90.

The lower ends of the downwardly extending portions of the L-shaped support members 87 and 90 are arranged so as to impinge on rubber bumpers or stops 92. The rubber stops are attached to the sides of the overall mechanized filing cabinet 11 by any suitable means such as bolts 94. The rubber bumpers 92 are located so that the downwardly projecting portion of the L-shaped support members 87 and 89 impinge on the bumpers when the door 23 is closed. This action raises the entire upper bar assembly and opens the first and second microswitches 69 and 71 by moving the tabs 65 and 67, respectively, away from the anns of the microswitches. In this manner, as will be between understood from the following description, unauthorized movement of the trays is prevented when the door is closed.

Coil springs 91 and 93 have their upper ends looped over the support members 87 and 89 and their lower ends looped through holes in the outer ends of the upper safety bar 27, The sprirlg force of coil springs 91 and 93 is such that the springs are stretched by the weight of the upper safety bar 27 and, its attached components. Hence, the upper safety bar 27 can be moved upwardly by applying an upward force beneath it. As the upper safety bar moves upwardly, the third and fourth generally U-shaped brackets 57 and 59 and their attached plates 61 and 63 move up. This movement moves tabs 65 and 67 away from the arms of the first and second microswitches 69 and 71, As previously described, this tab movement causes the microswitches 69 and 71 to open.

Mounted on one side of the upper safety bar 27 is the photocell housing 29 which houses a light-detecting element 95. Located on the other end of the upper safety bar is the lamp housing 31 which houses a lamp 97. Suitable optical elements 99 may be mounted in the lamp housing so as to collimate the beam from the lamp 97 and align it with the photocell 95.

It will be appreciated from the foregoing description of FIGS. 2 and 3 that the upper safety bar arrangement is such that a photocell is located on one side and a lamp is located on the other side of the bar. By suitably connecting the photocell 29 in a circuit that controls the application of energy to the motor driving the trays 15, when the light beam is broken, the motor will not be energized. In addition, by suitably connecting the first and second microswitches 69 and 71 in the same control circuit, energization of the motor can be prevented when the upper safety bar 27 is lifted. A simple circuit for providing these functions is illustrated in FIG. 6 and hereinafter described.

FIGS. 4 and 5 illustrate the lower safety bar arrangement for the invention. FIG. 4 illustrates the posting board 21 in phantom so that the lower safety bar assembly can be better illustrated. Connected beneath the posting board 21 and fixedly attached thereto are two downwardly projecting L-shapcd brackets 101 and 103. Projecting toward the rear of the posting board and each pivotally attached to the first and second L-shaped brackets 101 and 103 are two relatively long L- shaped (in cross section) arms 105 and 107. The arms swivel on the L-shaped brackets in a vertical plane. The lower safety bar 33 is fixedly attached to the outer ends of the arms 105 and 107. Two downwardly projecting brackets 109 and 111 project down from beneath the lower safety bar 33 at a point where the lower safety bar is attached to arms 105 and 107. Two coil springs 113, only one of which is visible in FIGS. 4 and 5, are looped at their lower ends through apertures in the downwardly projecting brackets. The upper ends of the coil springs are looped through L-shaped attachment brackets 1 17. The attachment brackets are fixedly attached to the bottom of the posting board 21.

A microswitch 119 is attached to each of the arms 105 and 107 The arms of the microswitches 1 l9 impinge on the lower surface of the posting board under normal conditions. Rubber bumpers l21 are mounted on the upper surface of the arms 105 and 107 so that they impinge on the lower surface of the posting board 21. The springs 113 are formed so that they have more force than the weight of the safety bar 33 and its attached components so that the microswitches are closed when no additional downward force is applied to the lower safety bar 33. As with the upper safety bar, the lower safety bar 33 has the photocell housing 35 mounted on one end and the lamp housing 37 mounted on the other end so that lamplight impinges on the light-sensitive surface of a light-detecting element unless the light beam is broken.

FIG. 6 is a simplified electrical schematic diagram used to illustrate more clearly how the lamp-photocell combinations and the microswitches control the application of energy to the tray movement motor. Assuming that the photocells are photo resistive devices wherein their resistance is low when a light beam impinges on their light-sensitive surface and high when a light beam is not so impinging, the photocells 131 and 133 of the upper and lower safety bars are connected in series with a voltage source 135 and the coil of a relay 137. The voltage source and relay are chosen such that when light beams are impinging on both photocells sufficient current flows through the relay coil 137 to close the relay contacts 139. However, when either or both light beams are broken, the current through the coil 137 drops sufficiently for the relay contacts 139 to open. It will be appreciated that if the photocells are voltage generating cells the voltage source 135 can be eliminated.

The relay contacts 139 are connected in series with the tray movement motor 141 and four microswitches 143, I45, I47 and 149.The series circuit is connected across a DC voltage source. Two of the microswitches are controlled by the upper safety bar in the manner heretofore described and the other two microswitches are controlled by the lower safety bar. It will be appreciated that, because FIG. 6 is a series circuit, opening of the relay contacts 139 or any of the microswitches 143, 145, 147 and 149 prevents the application of electrical energy to the motor 141.

Turning now to a description of the operation of the invention, normally the access opening 13 (FIG. 1) is open because the door 23 is raised. Under normal circumstances, the operator 17 presses a desired tray button and that tray moves to a point behind access opening 13 in a conventional and wellknown manner. However, if the arm of the operator is breaking the beam of either the lamp-photocell arrangements when the button is pushed, the motor will not be energized. Alternatively, if a file is projecting from a tray and breaks a beam when the operator presses s desired tray button, the motor will not be energized. Moreover, if when the motor is energized, a file projects outwardly but does not break one of the photocell beams, the trays will start to move. However, as soon as a file reaches either the upper photocell-lamp beam or the lower photocell-lamp beam, that beam will be broken and the motor will be deenergized. Similarly, if the trays are moving and an operator moves her arm into the opening so that her arm is caught by one of the trays, the arm will move until it breaks one of the photocell-lamp beams. At this point, the motor will immediately be deenergized and the trays will begin stopping. The distance traveled while stopping will be less than the distance the safety bar is allowed to travel, thus allowing an equivalent movement in the safety bar and hence not hurting the arm. Hence, the invention protects both the files and the operator of a mechanized filing cabinet.

In addition to preventing injury to the operator and damage to the files, the invention has an additional protection feature. Specifically, when the door 23 is slid down and closed, the upper safety bar structure impinges on the rubber stops 92. When this occurs, the upper safety bar structure moves upwardly and its associated microswitches open. As illustrated in FIG. 6 opening of these microswitches prevents the application of current to the tray movement motor. Hence, by closing and locking the door, tray movement as well as access to the trays is prevented.

It will be appreciated from the foregoing description that the invention provides a safety arrangement for use with mechanized filing cabinets. The safety arrangement allows the operator to sit or stand, as desired, because the posting board can be moved to any desired location. Moreover, the invention provides safety for the operator as well as safety for the files by preventing the operation or movement of the file trays when an object is projecting through the access opening. Finally, the invention prevents the movement of the filing trays when the machine is locked.

The embodiments of the invention is which an exclusive property or privilege is claimed are defined as follows:

1. A safety apparatus for use in a mechanized filing cabinet wherein any tray of a plurality of trays may be moved by an electric motor to an access opening, said filing cabinet also including a vertically sliding door for closing said access opening and a posting board projecting outwardly from said access opening, said safety apparatus comprising:

an upper safety bar assembly, said upper safety bar as sembly including:

an upper bar;

a first lamp mounted on one end of said upper bar so as to direct a beam of light toward the other end of said upper bar;

a first photocell mounted on the other end of said upper bar so as to intercept the beam of light from said first lamp; and

upper springs for hanging said upper bar from the lower edge of said sliding door of said mechanized filing cabinet in a vertically moveablemanner;

a lower safety bar assembly, said lower safety bar assembly including:

a lower bar;

a second lamp mounted on one end of said lower bar so as to direct a beam of light toward the other end of said lower bar;

a second photocell mounted on the other end of said lower bar so as to intercept the beam of light from said second lamp; and,

lower springs for hanging said lower bar from the rear of said posting board of said mechanized filing cabinet in a vertically movable manner; and,

electric circuit means connected to said first and second photocells and to said electric motor for preventing the application of electric power to said electric motor when either of said light beams is prevented from being intercepted by said first and second photocells.

2. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 1 wherein said upper springs exert less force than the weight of said upper safety bar assembly.

3. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 2 wherein said lower safety springs exert a greater force than the weight of said lower safety bar assembly.

4. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 3 including upper microswitches operably connected to said upper safety bar assembly and mounted on the back side of said sliding door, said microswitches mounted so as to be closed when said upper safety bar assembly is hanging against the upper spring force and open when said upper safety bar assembly is moved upwardly, said microswitches being connected to prevent the application of electric power to said electric motor when said upper safety bar is moved upwardly.

5. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 4 including lower microswitches operatively connected to said lower safety bar assembly so as to impinge on the underside of said posting board, said microswitches being closed with said lower safety bar assembly is in its normal raised position and open when said lower safety bar assembly is moved downwardly, said microswitches being connected so as to prevent the application of power to said electric motor when said lower safety bar assembly is moved downwardly.

6. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 5 wherein said lower safety bar assembly includes a pair of brackets attached to the lower side of said posting board, and a pair of rearwardly projecting arms connected to said brackets so as to swivel with respect to said brackets, said arms having said lower bar attached to their other ends so that said lower bar is located at the rear of said posting board. 

1. A safety apparatus for use in a mechanized filing cabinet wherein any tray of a plurality of trays may be moved by an electric motor to an access opening, said filing cabinet also including a vertically sliding door for closing said access opening and a posting board projecting outwardly from said access opening, said safety apparatus comprising: an upper safety bar assembly, said upper safety bar assembly including: an upper bar; a first lamp mounted on one end of said upper bar so as to direct a beam of light toward the other end of said upper bar; a first photocell mounted on the other end of said upper bar so as to intercept the beam of light from said first lamp; and upper springs for hanging said upper bar from the lower edge of said sliding door of said mechanized filing cabinet in a vertically moveable manner; a lower safety bar assembly, said lower safety bar assembly including: a lower bar; a second lamp mounted on one end of said lower bar so as to direct a beam of light toward the other end of said lower bar; a second photocell mounted on the other end of said lower bar so as to intercept the beam of light from said second lamp; and, lower springs for hanging said lower bar from the rear of said posting board of said mechanized filing cabinet in a vertically movable manner; and, electric circuit means connected to said first and second photocells and to said electric motor for preventing the application of electric power to said electric motor when either of said light beams is prevented from being intercepted by said first and second photocells.
 2. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 1 wherein said upper springs exert less force than the weight of said upper safety bar assembly.
 3. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 2 wherein said lower safety springs exert a greater force than the weight of said lower safety bar assembly.
 4. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 3 including upper microswitches operably connected to said upper safety bar assembly and mounted on the back side of said sliding door, said microswitches mounted so as to be closed when said upper safety bar assembly is hanging against the upper spring force and open when said upper safety bar assembly is moved upwardly, said microswitches being connected to prevent the application of electric power to said electric motor when said upper safety bar is moved upwardly.
 5. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 4 including lower microswitches operatively connected to said lower safety bar assembly so as to impinge on the underside of said posting board, said microswitches being closed with said lower safety bar assembly is in its normal raised position and open when said lower safety bar assembly is moved downwardly, said microswitches being connected so as to prevent the application of power to said electric motor when said lower safety bar assembly is moVed downwardly.
 6. A safety apparatus for use in a mechanized filing cabinet as claimed in claim 5 wherein said lower safety bar assembly includes a pair of brackets attached to the lower side of said posting board, and a pair of rearwardly projecting arms connected to said brackets so as to swivel with respect to said brackets, said arms having said lower bar attached to their other ends so that said lower bar is located at the rear of said posting board. 